High-output atmospheric water generator

ABSTRACT

An atmospheric water generator (AWG) may be used to extract water from ambient air. A compact screw compressor of the A WG may be used to compress refrigerant, a condenser of the A WG may be used to condense refrigerant, an expansion device, and an evaporator of the AWG may be used to transfer heat from ambient air to refrigerant, causing moisture in the air to condense. The condensed moisture may be collected in a water collection unit.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. Pat. application number16/053,680, filed Aug. 2, 2018, by Adam Van de Mortel, entitled“High-Output Atmospheric Water Generator” (atty. dock. no. 1404.349),which is hereby incorporated herein by reference in its entirety.

FIELD OF THE DISCLOSURE

The instant disclosure relates to atmospheric water generation. Morespecifically, portions of this disclosure relate to high outputatmospheric water generators.

BACKGROUND

In environments where clean and/or potable water may be in short supplyatmospheric water generators (AWGs) may be used to extract water fromambient air. Such extraction may be more efficient and cost effectivethan transporting water from an area where water is plentiful. Water maybe extracted from warm moist air by cooling the air, thus reducing amaximum humidity of the air and causing liquid water to condense.Through cooling, water can be extracted from the air when a clean and/orpotable water source, such as a freshwater body or rain, is unavailable.

Atmospheric water generators may remove moisture from the air by coolingthe air and collecting moisture that condenses as a result of thecooling, as shown in the AWG circuit diagram 100 of FIG. 1 . Forexample, a fluid substance, such as refrigerant, may be used inextracting moisture from the air. At a compressor 102, vapor refrigerantmay be compressed and/or heated. After it is compressed the vaporrefrigerant may be in a superheated state. At the condenser 104, thesuperheated vapor refrigerant may be cooled and condensed into liquidform. At the expansion valve 106, pressure may be reduced on the liquidrefrigerant, cooling the liquid further and reducing pressure on theliquid to transition it to a liquid/vapor refrigerant mixture. At theevaporator 108 the refrigerant may absorb heat from air adjacent to therefrigerant to condense water vapor from the air. When passing throughthe evaporator 108 the liquid/vapor refrigerant mixture may warm,transitioning it to saturated/superheated vapor state. Then, the vaporrefrigerant may be passed to the compressor 102. Fan 110 may move airacross the evaporator 108 to replace dry air from which water has beenextracted with moist air. Thus, water vapor may be extracted from theambient air by cooling the air to cause the water vapor to condense intoliquid water.

Atmospheric water generators, however, can be bulky and inefficient.AWGs may have low water production capacities, requiring multiple unitsto produce a desired amount of water. For example, many AWGs usetraditional scroll or reciprocating compressors to compress refrigerant,which have limited capacity. Given their limited capacity, multiplesmall scroll or reciprocating compressors may be required to realizesubstantial water output. Larger traditional screw type compressorsrequire external oil cooling, external oil separators, and additionalcooling capacity to cool the compressor. Traditional screw, scroll orreciprocating compressors may also be difficult and cumbersome toinstall and may have a bulky form factor, making such compressors lessthan ideal for modular or mobile operation. AWGs may also incorporatefin-tube coil condensers and evaporators made of copper tubing withaluminum fins. Fin-tube coils may be inefficient, bulky, heavy, andexpensive and may have low heat transfer rates. Thus, atmospheric watergenerators may be bulky and inefficient with limited productioncapacity.

Shortcomings mentioned here are only representative and are includedsimply to highlight that a need exists for improved atmospheric watergenerators, particularly for high-output atmospheric water generators.Embodiments described herein address certain shortcomings but notnecessarily each and every one described here or known in the art.Furthermore, embodiments described herein may present other benefitsthan, and be used in other applications than, those of the shortcomingsdescribed above.

SUMMARY

A high-output atmospheric water generator (AWG) may use advanced vaporcompression refrigeration technology to deliver water at higher ratesthan conventional generators using one or more compact screw compressorsto drive a refrigeration cycle, using vapor compression refrigeration toproduce cooling and extract water from ambient air. Inclusion of compactscrew compressors in place of traditional screw, scroll or reciprocatingcompressors enhances the efficiency of an AWG, reduce the weight of anAW G, and reduce the bulk of an AWG. The smaller size and weight of thecompact screw compressor may allow production of AWGs as modular unitsfor easy transportation and remote deployment. For example, the compactscrew compressor may not require external motors, oil filters, oilreservoirs, and oil cooling systems. Additionally, compact screwcompressors may have a higher refrigerating capacity than scroll orreciprocating compressors allowing for enhanced water productioncapacity. Compact screw compressors are also more efficient than scrollor reciprocating compressors, requiring less energy to operate the AW G.For example, compact screw compressors have a higher energy efficiencyratio (EER) than scroll or reciprocating compressors. Compact screwcompressors may also incorporate high flow connection piping andisolation valves to further maximize EER. Compact screw compressors mayalso be precision-tuned to maximize efficiency through control of motorspeed.

A high-output atmospheric water generator may also incorporatemicrochannel heat exchange coil evaporators and condensers to furtherincrease efficiency and reduce bulk and weight. Microchannel heatexchange coil evaporators and condensers may have a higher efficiencythan fin-tube style coils. For example, microchannel heat exchange coilevaporators and condensers may have higher heat transfer rates, closerapproach temperatures, and lower airside pressure drops. Microchannelheat exchange coil evaporators and condensers may also take up lessspace and weigh less than fin-tube style coils. The reduced weight andarea of microchannel heat exchange coil systems may allow for increasedwater production in a reduced form factor. For example, modular AWGunits may be designed in a smaller form factor for easiertransportation, while maintaining or increasing water productioncapacity. Microchannel heat exchange coil evaporators and condensers mayalso require less refrigerant to operate than fin-tube style coils,further reducing weight and operating cost. Thus, through use ofmicrochannel heat exchange coil evaporators and condensers, theefficiency and production capacity of an AWG may be enhanced, whilereducing the weight, bulk, and operating cost of the unit.

An atmospheric water generator may include a first condenser to condenserefrigerant in a liquid state. For example, the condenser may transformrefrigerant from a high pressure superheated vapor state to ahigh-pressure subcooled liquid state. The condenser may be a finned heatexchanger and may include a microchannel condenser coil. An outlet ofthe condenser may be coupled to an inlet of an expansion device, such asa capillary tube or expansion valve. The expansion device may reducepressure on and further cool the refrigerant before it enters anevaporator. An outlet of the expansion device may be coupled to an inletof a first evaporator. The first evaporator may be a finned heatexchanger and may condense water from adjacent air at air fins bytransferring heat from the air to the refrigerant. For example, therefrigerant may be cold when it enters the evaporator, causing airaround the evaporator to cool, reducing the amount of moisture the airis capable of holding and causing condensation to form. The firstevaporator may include a microchannel evaporator coil. A watercollection unit may collect water condensed by the first evaporator. Forexample, the first evaporator may be positioned to cause condensation toflow into the water collection unit. An outlet of the first evaporatormay be coupled to an inlet of a first compact screw compressor. Thecompact screw compressor may compress refrigerant. For example, thecompact screw compressor may receive subcooled refrigerant vapor fromthe evaporator, may heat and compress the refrigerant vapor, and mayoutput superheated refrigerant vapor to the condenser via an outlet ofthe compressor coupled to an inlet of the condenser.

A water collection unit may collect water condensed by the firstevaporator. For example, the first evaporator may be positioned to causecondensation to flow into the water collection unit. An output of thewater collection unit may be coupled to a water treatment system tosterilize, filter, and mineralize the water condensed by the evaporator.The water treatment system may, for example, include one or morefilters. The AWG may also include a double diaphragm water condensatepump to pump water from the water collection unit through the watertreatment system. A high-output AWG may have a water production capacityup to or exceeding approximately 10,000 gallons per day and may producewater that is safe for human consumption.

The AWG may include one or more fans, such as vane-axial fans, to moveair through the system. For example, one or more vane-axial fans canexpel cooled air from which moisture has been extracted from the AWGwhile pulling warm moist air into the AWG. The vane-axial fans mayfurther act to move cooled air across a condenser to cool therefrigerant in the condenser before expelling the air.

The AWG may include a subcooling heat exchange system coupled betweenthe condenser outlet and the evaporator inlet to further coolrefrigerant flowing from the condenser to the evaporator. The subcoolingheat exchange system may, for example, provide additional cooling of therefrigerant to enhance the efficiency and output of microchannelcondensers and evaporators. In some embodiments, the subcooling heatexchange system may be coupled between the outlet of the condenser andthe inlet of the expansion device. The additional refrigerant coolingprovided by the subcooling system may also provide increased operationalflexibility in environments with higher ambient temperatures. Thesubcooling heat exchange system may include one or more direct expansionheat exchangers to transfer cooling from refrigerant of a discretesubcooling heat exchange circuit to refrigerant of the primary AWGcircuit, described above. The subcooling system may further include aheat rejection unit to cool the subcooling heat exchange system. Theheat rejection unit may include one or more airfoil axial fans to coolthe subcooling system. Airflow of the subcooling system provided by theone or more airfoil axial fans may be isolated from the firstevaporator.

The AWG may include one or more variable frequency drives (VFDs)configured to control one or more motors of the system. For example, thevariable frequency drives may control speeds of the compact screwcompressors, the airfoil axial fans, the vane-axial fans, and othermotors of the system. Variable frequency drives may be used to tune fanspeeds in the AWG, in both the main water extraction system and thesubcooling system to tune airflow for maximum water extraction. Avariable frequency drive may control a pump for transferring water fromthe water collection unit through the water treatment system.

In some embodiments, the first condenser, expansion device, evaporatorand compact screw compressor may form a first AWG circuit. A second AWGcircuit, including a second condenser, a second expansion device, asecond evaporator, and a second compact screw compressor, may share awater collection unit to collect water from the first evaporator and thesecond evaporator. The first and second AWG circuits may also share awater treatment system for sterilizing, filtering, and mineralizingwater from the shared water collection unit.

A method for condensing water may include compressing refrigerant usinga first compact screw compressor. The refrigerant may then betransferred from the first compact screw compressor to a firstcondenser. The refrigerant may then be condensed to a liquid state bythe first condenser. After the refrigerant is condensed, it may betransferred to an expansion device. The expansion device may reduce thepressure on and further cool the refrigerant. The refrigerant may thenbe transferred to a first evaporator. Water may be condensed from airadjacent to the first evaporator by transferring heat from the airadjacent to the first evaporator to refrigerant inside the firstevaporator. Refrigerant may then be transferred from the firstevaporator to the first compact screw compressor.

Dry, cool, air from an area adjacent to the first evaporator may beremoved and replaced with moist air using a vane-axial fan. In someembodiments, the refrigerant may be further cooled while it is beingtransferred from the first condenser to the first expansion device usinga subcooling heat exchange system to absorb heat from the refrigerant.The subcooling heat exchange system may be further cooled using a heatrejection unit of the subcooling heat exchange system.

Water condensed by the evaporator may be collected in a water collectionunit and a pump may be operated to transfer the collected water througha water treatment system to treat the collected water. Additionalcompact screw compressors, condensers, expansion devices, andevaporators may be included in additional AWG circuits for performingsteps of condensing refrigerant, cooling refrigerant, transferringrefrigerant, and condensing water from the air by transferring heat fromthe air to the refrigerant. In some embodiments, multiple AWG circuitsmay share a water collection unit and water treatment system.

In some embodiments, one or more AWG circuits and subcooling heatexchange systems may be packaged in an AWG module. For example, multiplediscrete AWG modules may include sets of one or more compact screwcompressors, one or more condensers, one or more expansion devices andone or more evaporators. Discrete AWG modules may each have individualwater collection units, pumps, and water treatment systems, or they mayshare water collection units, pumps, and water treatment systems.

The foregoing has outlined rather broadly certain features and technicaladvantages of embodiments of the present invention in order that thedetailed description that follows may be better understood. Additionalfeatures and advantages will be described hereinafter that form thesubject of the claims of the invention. It should be appreciated bythose having ordinary skill in the art that the conception and specificembodiment disclosed may be readily utilized as a basis for modifying ordesigning other structures for carrying out the same or similarpurposes. It should also be realized by those having ordinary skill inthe art that such equivalent constructions do not depart from the spiritand scope of the invention as set forth in the appended claims.Additional features will be better understood from the followingdescription when considered in connection with the accompanying figures.It is to be expressly understood, however, that each of the figures isprovided for the purpose of illustration and description only and is notintended to limit the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the disclosed system and methods,reference is now made to the following descriptions taken in conjunctionwith the accompanying drawings.

FIG. 1 is a circuit diagram of an AWG circuit, according to the priorart.

FIG. 2 is a diagram of an example AWG according to some embodiments ofthe disclosure.

FIG. 3 is a perspective view of a modular AWG dissembled for shippingaccording to some embodiments of the disclosure.

FIG. 4 is a perspective view of an assembled modular AWG according tosome embodiments of the disclosure.

FIG. 5 is a perspective view of a microchannel condenser coil accordingto some embodiments of the disclosure.

FIG. 6 is a perspective view of a microchannel evaporator coil accordingto some embodiments of the disclosure.

FIG. 7 is perspective view of a portion of a microchannel coil accordingto some embodiments of the disclosure.

FIG. 8 is a circuit diagram of an AWG circuit having a subcooleraccording to some embodiments of the disclosure.

FIG. 9 is a circuit diagram of a subcooler circuit cooling two parallelAWG circuits according to some embodiments of the disclosure.

FIG. 10 is a perspective view of a subcooling plate heat exchangeraccording to some embodiments of the disclosure.

FIG. 11 is a block diagram of a heat rejection unit according to someembodiments of the disclosure.

FIG. 12 is a perspective view of a plurality of condensers of asubcooler according to some embodiments of the disclosure.

FIG. 13 is a perspective view of a plurality of airfoil axial fans of asubcooler according to some embodiments of the disclosure.

FIG. 14 is an example method of extracting water from air according tosome embodiments of the disclosure.

DETAILED DESCRIPTION

High-output atmospheric water generators may be used to generate a watersupply by extracting moisture from ambient air. Refrigerant may becycled through the AWG to cool air, causing water in the air tocondense. Fans may move air through the AWG so that when air is cooledand water is extracted warm, moist, air may be brought in to replace thecool dry air for continued water extraction. High-output atmosphericwater generators can produce in excess of 10,000 gallons of water a day.

An example atmospheric water generator 200, shown in FIG. 2 , mayinclude a first AWG refrigerant circuit having a compressor 202, acondenser 204, an expansion device 206, and an evaporator 208. Thecompressor 202 may be a compact screw compressor. Compact screwcompressors may use meshing screws, or rotors, to create a constant, ornear constant, flow and compression of gas or fluid inside thecompressor. The constant flow can limit pulsation and provide a constantor near constant flow of refrigerant in the AWG 200. Compact screwcompressors can provide a variety of advantages over traditional screwcompressors or compressors traditionally incorporated in AWGs, such asscroll or reciprocating compressors. For example, compact screwcompressors may be more efficient, lighter, more compact, and easier tomaintain and assemble than traditional screw, scroll, or reciprocatingcompressors. Compact screw compressors may also provide a fine degree ofcontrol over coolant pressure and speed of movement in the AWG systemnot present in systems with scroll or reciprocating compressors. Thecompact screw compressor 202 may compress refrigerant, outputting therefrigerant in a superheated gaseous state.

The superheated gaseous refrigerant may be received by a condenser 204which may condense the refrigerant into a saturated or subcooled liquid.The condenser 204 may cool the refrigerant to cause it to condense intoa liquid state. The condenser 204 may be a microchannel condenser coil,passing refrigerant through small channels to enable more efficientcondensation of the refrigerant.

The subcooled liquid refrigerant may be passed from the condenser 204 toan expansion device 206. The expansion device 206 may further cool therefrigerant by reducing pressure on the refrigerant. The expansiondevice 206 may, for example, be an expansion valve or a capillary tube.The expansion device 206 may include one or more independent actingmicrocontrollers to control operation of the expansion device 206 andgovern the rate and pressure at which refrigerant is passed to theevaporator 208. Due to the decreased pressure, the refrigerant outputfrom the expansion device 206 may be a mixture of liquid and vapor.

The refrigerant may be passed from the expansion device 206 to theevaporator 208. Evaporator 208 may allow heat from air adjacent toevaporator 208 to be transferred to the refrigerant inside, therebyreducing the temperature of the air. The reduction of temperature of theair may cause water to condense. The evaporator may for example be amicrochannel evaporator coil. Similar to microchannel condenser coils,microchannel evaporator coils pass refrigerant through small channels toenable more efficient heat transfer from the air to the refrigerant. Theheat transfer from the air to the refrigerant may cause the remainingliquid refrigerant to vaporize. The vapor refrigerant may then be passedback to compressor 202 to continue the cycle.

Water condensed by the evaporator 208 may be collected in a watercollection unit 210 for accumulation and pump feed. Water collectionunit 210 may, for example, be made of stainless steel. Water treatmentsystem 216 may include a bacteria control system, particulatefiltration, and mineralization to purify water pumped from watercollection unit 210. When water is needed, pump 214 may operate totransfer water from water collection unit 210 through the watertreatment system 216. Pump 214 may, for example, be a food-safe,run-dry, self-priming, double diaphragm, water condensate pump. Watertreatment system 216 may treat water so that the water is fit for humanconsumption. After passing through water treatment system 216, the watermay pass through water line 222 to an output of the AWG 200. The watertreatment system 216 may not be included, may be internal to each AWGmodule, or may be external with multiple AWG modules sharing a singlewater treatment system 216. For example, the water line 222 may becoupled to bulk use or a water treatment skid for drinking water.

Air may be moved through the AWG 200 using fan 220. Fan 220 may be avane-axial fan. Although a single fan is shown, multiple fans may beused to move air through the AWG 200. For example, the fan 220 may movewarm moist air into the unit through electrostatic air filter 218. Thewarm, moist air may then be channeled around evaporator 208 which maycool the air, causing moisture in the air to be condensed into watercollection unit 210. Fan 220 may then move the cool dry air around thecondenser, where the air may absorb heat from the refrigerant in thecondenser, causing the refrigerant to condense more efficiently. Thewarmed air may then be expelled from the AWG 200 by fan 220. Airflow inthe AWG 200 may be designed, using vane-axial fan 220, to producepartial airflow through a controlled portion of the AWG 200 around theevaporator 208 with a bypass stream allowing partial airflow bypassingthe evaporator 208. The two partial streams may combine for full airflowcooling condenser 204 and expulsion from the AWG 200. The use of abypass airstream can help to minimize water entrainment in air that isexpelled from the AWG by the fan 220.

Motors of the AWG 200 may be controlled by controller 224. Controller224 may include a variable frequency drive (VFD) or a plurality of VFDs.Controller 224 may control fan 220, expansion device 206, pump 214, andcompact screw compressor 202. The use of variable frequency drives bycontroller 224 to drive components may allow the compressor 202, fan220, and pump 214 to run continuously and ramp up/down in speed whenstarted or stopped. Variable frequency drives can thus smooth powerconsumption and reduce overall peak power demand.

Variable frequency drives can also be manually adjusted to optimizemotor speed for each component of the AWG 200. Controller 224 mayinclude a programmable logic controller (PLC). The PLC may include acolor touchscreen interface for programming operational sequencing ofthe AWG 200 including ramping functions for the motor drives, such asvariable frequency drives, pumpdown sequences, and maintenance andtuning modes for the AWG 200. Controller 224 may monitor a variety ofprocess variables of the AWG 200, such as coil face temperatures in thecondenser 204 and evaporator 208. If controller 224 detects operationoutside of predetermined operating ranges, such as predeterminedtemperature ranges, it may take action to safeguard equipment andpersonnel, such as by shutting down the AWG 200. Controller 224 may alsoconnect to the internet to allow remote access and telemetry of the AWG200 and to provide notifications regarding system status andmaintenance. The controller 224 may also control a plurality ofstep-motor electric expansion valves (not shown) to control the flow ofrefrigerant in the system. For example, through the step-motor electricexpansion valves, the controller 224 may control main operation of theAWG refrigerant circuit while allowing manual adjustment of theoperation of speeds of the fan 220, compressor 202, and pump 214 to tunethe system during startup or to trim control during operation. In someembodiments, fan 220 may be driven by a direct drive motor with speedcontrol.

In some embodiments, two or more AWG refrigerant circuits may be coupledin parallel to increase water output. For example, an AWG circuitsimilar or identical to the AWG refrigerant circuit of FIG. 2 includingcondenser 204, expansion device 206, evaporator 208, and compact screwcompressor 202 may be coupled in parallel to the AWG circuit of FIG. 2 .The two circuits may share fans 220, air filters 218, a single watercollection unit 210, a pump 214, water treatment system 212, and acontroller 224, or each system may have its own water collection andtreatment, air movement, and control components. Multiple AWGrefrigerant circuits, such as the AWG refrigerant circuit shown in FIG.2 , may be included in a single AWG module. Two parallel AWG modules canproduce water output up to and exceeding 20,000 gallons per day.

An AWG may be packaged as an AWG module for easy shipping andinstallation. An example AWG module 300 is shown in FIG. 3 . As shown inFIG. 3 , the AWG module 300 is packaged for easy shipping in arectangular form factor. Protective plates 302A-B may cover attachmentopenings for one or more external fans, such as vane-axial fans.Protective plates 304A-B, 306A-B, and 308 may cover air intake andoutput openings and/or filters. The AWG module 300 may ship withrefrigerant precharged to simplify installation. The enclosure may, forexample, be produced with climate control to operate in both hot andcold climates. When the AWG module 300 is delivered, plates 302A-B304A-B, 306A-B, and 308 may be removed.

The AWG module may be assembled at the operation site. An exampleassembled AWG module 400 is shown in FIG. 4 . When an AWG module, suchas AWG module 300 of FIG. 3 , is delivered, the AWG may be quicklyassembled by bolting fans 402AB, which may be vane-axial fans, to thetop of AWG 400, and adding filter media holders, screens, and/or filtersto air intakes 404A-B and 406A-B. Fans 402A-B, which may be shippedseparately, may be attached to the top of AWG module 400, where plates302A-B had previously been attached. Fans 402A-B may be driven usingdirect drive motors with speed control. Air intakes 404A-B may allow airto be pulled into the AWG module 400 by fans 402A-B for moistureextraction. Air intakes 404A-B may include air filters such asantimicrobial MERV9 rated filters. Air intakes 406A-B may also allow airintake into the AWG 400. Air intakes 406A-B may also include air filterssuch as antimicrobial MERV9 rated filters. Fans inside outputs 408A-Bmay pull air in through intakes 406A-B and expel air through outputs408A-B. Filters for air intakes 404A-B and 406A-B may ship separatelyfrom the AWG 300 shown in FIG. 3 . Airflow from intakes 404A-B to fans402A-B may be isolated from airflow from intakes 406A-B to outputs408A-B. For example, airflow from intakes 404A-B to fans 402A-B maysupply air to an AWG for moisture extraction, while airflow from intakes406A-B to outputs 408A-B may cool a subcooling system of the AWG module400.

Microchannel condenser coils can enhance the efficiency and waterproduction of an AWG. An example two-row series-flow microchannelcondenser coil 500 is shown in FIG. 5 . The microchannel condenser coil500 may receive superheated vapor refrigerant via an intake 502, andpass the refrigerant through multiple small channels on the right andthe left. The condenser 500 may cool the refrigerant throughtransferring heat from the refrigerant to air around the condenser 500.The small size of the channels can enhance the operation of thecondenser allowing more rapid and efficient heat transfer between therefrigerant and the air. The cooling of the refrigerant may cause thevapor refrigerant to condense so that a cooled liquid refrigerant isoutput from the condenser 500 via output 504. The microchannel condensercoil 500 may consist of multiple manifolded braised modules. Multiplecondenser coils may be included in an AWG system, such as AWG 200 shownin FIG. 2 .

Microchannel evaporator coils can also enhance the efficiency and waterproduction of an AWG. An example two-row parallel-fed microchannelevaporator coil 600 is shown in FIG. 6 . The microchannel evaporatorcoil 600 may receive cooled liquid/vapor mix refrigerant at inlets 602,604 and may pass the refrigerant through multiple small channels on theright and the left. The small size of the channels can enhance theoperation of the evaporator allowing more rapid and efficient heattransfer between the refrigerant and the air and thus more efficientwater extraction. As it passes through the channels, the refrigerant mayabsorb heat from ambient air, causing water to condense and be collectedby the microchannel evaporator coil 600. The microchannel evaporatorcoil 600 may output warmed liquid refrigerant at outlet 606 andcollected water from its fins, which gravity may drain to a watercollection unit located below the microchannel evaporator coil 600. Themicrochannel evaporator coil 600 may consist of multiple manifoldedbrazed modules. Multiple evaporator coils may be included in an AWGsystem, such as AWG 200 shown in FIG. 2 .

An example perspective view 700 of a microchannel coil is shown in FIG.7 . Headers 702A-B may conduct refrigerant to and away from themicrochannels 704AB. The microchannels may conduct refrigerant alongintegrally brazed fin 706 to facilitate heat transfer betweenrefrigerant and the ambient air. Integrally brazed fin 706 may allow airflow along microchannels 704A-B and facilitate condensation of waterfrom the air, in microchannel evaporators. Thus, a microchannelevaporator or condenser coil may facilitate more efficient heat transferbetween refrigerant and ambient air.

A subcooling system may be used to further cool refrigerant of an AWGsystem, such as the AWG shown in FIG. 2 , and may improve the efficiencyand output of the AWG system. For example, in AWG systems incorporatingmicrochannel evaporator and condenser coils, it may be necessary toreduce refrigerant velocities to maintain efficient operation. Use of asubcooling system to further cool refrigerant can allow the necessaryvelocity reduction while maintaining a desired temperature of therefrigerant when entering an evaporator. An example AWG 800 including asubcooling circuit heat exchanger 806 is shown in FIG. 8 . Therefrigerant circuit of AWG 800 may include a compressor 802, a condenser804, a subcooling heat exchanger 806, an expansion valve 808, and anevaporator 810. A compressor 802, such as a compact screw compressor,may compress refrigerant and output vapor refrigerant to a condenser804, such as a microchannel heat exchange coil condenser. The condenser804 may cool and condense the refrigerant with air flow provided byfan(s) 812. The condenser 804 may output liquid condensed refrigerant toa subcooling system heat exchanger 806. The liquid refrigerant output bythe condenser may, in some embodiments, be at a temperature higher thanthe ambient temperature. The subcooling circuit heat exchanger 806 mayfurther cool the refrigerant and may bring the temperature of the liquidrefrigerant down to well below ambient temperature. The subcoolingcircuit 806 may output the refrigerant to an expansion valve 808 tofurther cool the refrigerant and transform it to a liquid and vapormixture. The liquid and vapor mixture may be output by an expansionvalve 808 to an evaporator 810, such as a microchannel heat exchangecoil evaporator, to extract moisture from air moved across theevaporator 810 by fan(s) 812. The evaporator 810 may then outputrefrigerant to the compressor 802. Controller 816 may control theoperation of compressor 802, expansion valve 808, and fan(s) 812.

An example subcooling system 900 is shown in FIG. 9 . The subcoolingsystem 900 may include a refrigerant circuit that is separate from therefrigerant circuit of the AWG 800. A compressor 902, such as a compactscrew compressor may compress refrigerant and may output superheatedvapor refrigerant to a condenser 904, such as a microchannel heatexchange coil condenser. Condenser 904 may condense the refrigerant to aliquid form, allowing heat to transfer from the refrigerant to air flowsupplied by fan 910. Condenser 904 may output liquid refrigerant to anexpansion valve 906A which may reduce pressure on the refrigerant,further cooling the refrigerant and transitioning the refrigerant to aliquid and vapor mixture. The refrigerant may then absorb heat from theAWG refrigerant circuit 908A. For example, the refrigerant of thesubcooling system 900 may absorb heat from the refrigerant of the AWGcircuit via heat exchanger 908A, for example as in AWG 200 of FIG. 2 orAWG 800 of FIG. 8 . The refrigerant may then be passed to the compressor902 to continue the cycle. In some embodiments, multiple subcoolingpaths including expansion valves 906A-B may be used to cool the AWG viaheat exchangers 908A-B. In other embodiments, the multiple subcoolingpaths may cool multiple AWG refrigerant circuits via heat exchangers908A-B. Thus, an AWG may, in some embodiments, have three or morerefrigerant circuits: two or more AWG refrigerant circuits and asubcooling circuit to cool the two or more AWG refrigerant circuits.

A subcooling system may include one or more subcooling plate heatexchanges to facilitate exchange of heat between refrigerant of an AWGrefrigerant circuit and refrigerant of the subcooling system. An exampleplate heat exchanger 1000 is shown in FIG. 10 . A front view 1002A ofthe plate heat exchanger 1000 is shown, in addition to a side view 1002Bof the plate heat exchanger 1000. The plate heat exchanger 1000 may, forexample, act as an evaporator transferring heat from refrigerant of oneor more AWG refrigerant circuits to refrigerant of the subcoolingcircuit. Plate heat exchangers may provide direct refrigerant-torefrigerant efficient heat transfer in a compact design with lowrefrigerant pressure drops to increase the efficiency of the system.

An AWG may also include a heat rejection unit (HRU) to cool thesubcooling system. For example, the HRU may include one or moremicrochannel coil condensers for condensing refrigerant and passing theheat from the refrigerant to ambient air. The air flow through the HRUmay be isolated from the air flow of an AWG refrigerant circuit. Anexample HRU 1100 is shown in FIG. 11 . The HRU 1100 may include amachine room 1102 housing components 1106 of the subcooling system, suchas compressors, pumps, electrical panels, and variable frequency drives.Air may enter the machine room 1102 through filters 1104A-B. Forexample, filters 1104A-B may include flow matched filtered suctionpanels to prevent contaminants in external air from entering the machineroom 1102. A subcooling system 1108 including microchannel coilcondensers, which may be located in the machine room 1102 or external tothe machine room 1102, may be cooled using the HRU 1100. The HRU may useairfoil axial fans 1110 to pull air through the filters 1104A-B andacross the microchannel coil condensers of the subcooling system 1108 tofurther cool refrigerant of the subcooling system 1108. The airfoilaxial fans 1110 may be driven by one or more variable frequency drives.Thus, the HRU 1110 may provide additional cooling airflow to thesubcooling system isolated from airflow of the AWG refrigerant circuit,and an evaporator of the AWG refrigerant circuit in particular.Separation of the HRU airflow from the airflow of the AWG refrigerantcircuit may increase efficiency and water production of the AWG and mayalso allow water production at higher ambient temperatures, due topre-cooling of liquid refrigerant in the AWG refrigerant circuit.

An example perspective view of the HRU 1200 is shown in FIG. 12 . TheHRU 1200 may include multiple condensers 1202A-B coupled to coolrefrigerant from refrigerant line 1204. Airfoil axial fans 1302, 1304,illustrated in the top-down view of an example HRU 1300 in FIG. 13 , maypull air up, through the condensers 1202A-B and expel air from the HRU1200 of FIG. 12 and 1300 of FIG. 13 . Thus, the HRU may provideadditional cooling to the subcooling system.

An example method 1400 of extracting water from ambient air using an AWGis shown in FIG. 14 . The method 1400 may begin, at step 1402, withcompressing refrigerant. For example, refrigerant may be compressedusing a compact screw compressor. At step 1404, the refrigerant may betransferred from the compressor to a condenser. The condenser may, forexample, include a microchannel condenser coil. At step 1406, thecondenser may condense refrigerant. Condensing the refrigerant mayinclude cooling the refrigerant. At step 1408, the refrigerant may betransferred from a condenser to an evaporator. At step 1410, therefrigerant may be transferred to an expansion device. At step 1412,while the refrigerant is being transferred from the condenser to theexpansion device, the refrigerant may be cooled further. For example,the refrigerant may be cooled by a subcooling system. At step 1412, theexpansion device may reduce pressure on and further cool therefrigerant. At step 1414, the refrigerant may be transferred from theexpansion device to the evaporator. At step 1416, water may be condensedfrom ambient air by the evaporator. The evaporator may, for example,include a microchannel evaporator coil to facilitate heat exchangebetween refrigerant and ambient air to cool the ambient air causingcondensation to form. At step 1418, the condenser may be cooled. Forexample, one or more fans, such as vane-axial fans, may be used to drawair across the evaporator, to cool the air and extract water from theair, and across the condenser, to cool refrigerant inside the condensercausing it to condense. At step 1420, the refrigerant may be transferredfrom the evaporator to the compressor. In some embodiments, the method1400 may repeat indefinitely, until a controller or manual inputdeactivates the AWG.

The schematic flow chart diagram of FIG. 14 is generally set forth as alogical flow chart diagram. As such, the depicted order and labeledsteps are indicative of aspects of the disclosed method. Other steps andmethods may be conceived that are equivalent in function, logic, oreffect to one or more steps, or portions thereof, of the illustratedmethod.

Additionally, the format and symbols employed arc provided to explainthe logical steps of the method and are understood not to limit thescope of the method. Although various arrow types and line types may beemployed in the flow chart diagram, they are understood not to limit thescope of the corresponding method. Indeed, some arrows or otherconnectors may be used to indicate only the logical flow of the method.For instance, an arrow may indicate a waiting or monitoring period ofunspecified duration between enumerated steps of the depicted method.Additionally, the order in which a particular method occurs may or maynot strictly adhere to the order of the corresponding steps shown.

If implemented in firmware and/or software, functions described abovemay be stored as one or more instructions or code on a computer-readablemedium. Examples include non-transitory computer-readable media encodedwith a data structure and computer-readable media encoded with acomputer program. Computer-readable media includes physical computerstorage media. A storage medium may be any available medium that can beaccessed by a computer. By way of example, and not limitation, suchcomputer-readable media can comprise random access memory (RAM),read-only memory (ROM), electrically-erasable programmable read-onlymemory (EEPROM), compact disc read-only memory (CD-ROM) or other opticaldisk storage, magnetic disk storage or other magnetic storage devices,or any other medium that can be used to store desired program code inthe form of instructions or data structures and that can be accessed bya computer. Disk and disc includes compact discs (CD), laser discs,optical discs, digital versatile discs (DVD), floppy disks and Blu-raydiscs. Generally, disks reproduce data magnetically, and discs reproducedata optically. Combinations of the above should also be included withinthe scope of computer-readable media.

In addition to storage on computer readable medium, instructions and/ordata may be provided as signals on transmission media included in acommunication apparatus. For example, a communication apparatus mayinclude a transceiver having signals indicative of instructions anddata. The instructions and data are configured to cause one or moreprocessors to implement the functions outlined in the claims.

Although the present disclosure and certain representative advantageshave been described in detail, it should be understood that variouschanges, substitutions and alterations can be made herein withoutdeparting from the spirit and scope of the disclosure as defined by theappended claims. Moreover, the scope of the present application is notintended to be limited to the particular embodiments of the process,machine, manufacture, composition of matter, means, methods and stepsdescribed in the specification. As one of ordinary skill in the art willreadily appreciate from the present disclosure, processes, machines,manufacture, compositions of matter, means, methods, or steps, presentlyexisting or later to be developed that perform substantially the samefunction or achieve substantially the same result as the correspondingembodiments described herein may be utilized. Accordingly, the appendedclaims are intended to include within their scope such processes,machines, manufacture, compositions of matter, means, methods, or steps.

1. An apparatus comprising: an atmospheric water generator comprising: acompressor configured to compress refrigerant; a condenser configuredcondense the refrigerant to a liquid state; an expansion deviceconfigured to reduce pressure and temperature of the refrigerant; anevaporator configured to condense water from air by transferring heatfrom the air to the refrigerant; a subcooling system for absorbing heatfrom the atmospheric water generator; and a controller operable forcontrolling the atmospheric water generator and the subcooling system.2. The apparatus of claim 1, wherein: the subcooling system comprisesone or more direct expansion heat exchangers.
 3. The apparatus of claim1, wherein: the subcooling system comprises one or more heat rejectionunits.
 4. The apparatus of claim 3, wherein: the one or more heatrejection units comprises one or more fans.
 5. The apparatus of claim 4,wherein: airflow of the subcooling system is isolated from theevaporator of the atmospheric water generator.
 6. The apparatus of claim1, further comprising: a container configured to collect the watercondensed by the evaporator.
 7. The apparatus of claim 6, furthercomprising: a water treatment system; a pump for pumping water from thecontainer and through the water treatment system; a water line forpassaging water from the water treatment system to an output of theapparatus; and the controller further operable for controlling the pump.8. The apparatus of claim 1, further comprising: a water treatmentsystem for receiving water condensed by the evaporator.
 9. The apparatusof claim 8, wherein: the water treatment system is operable tosterilize, filter, and mineralize the collected water.
 10. The apparatusof claim 1, wherein: the compressor comprises an inlet coupled to anoutlet of the evaporator and an outlet coupled to an inlet of thecondenser; the expansion device comprises an inlet coupled to an outletof the condenser; the evaporator comprises an inlet coupled to an outletof the expansion device; and the subcooling system is coupled betweenthe condenser outlet and the evaporator inlet.
 11. The apparatus ofclaim 10, wherein: the compressor comprises a compact screw compressor;the condenser comprises microchannel coils; and the evaporator comprisesmicrochannel coils.
 12. An apparatus comprising: a first atmosphericwater generator comprising: a first compressor configured to compressrefrigerant; a first condenser configured to receive the refrigerant toa liquid state; a first expansion device configured to reduce pressureand temperature of the refrigerant; a first evaporator configured tocondense water from air by transferring heat from the air to therefrigerant; a second atmospheric water generator comprising: a secondcompressor configured to compress refrigerant; a second condenserconfigured to receive the refrigerant to a liquid state; a secondexpansion device configured to reduce pressure and temperature of therefrigerant; a second evaporator configured to condense water from airby transferring heat from the air to the refrigerant; and a containerconfigured to collect water condensed by the first evaporator and watercondensed by the second evaporator.
 13. The apparatus of claim 12,further comprising: a water treatment system to treat the collectedwater from the first evaporator and the second evaporator.
 14. Theapparatus of claim 13, wherein: the water treatment system is operableto sterilize, filter, and mineralize the collected water.
 15. Theapparatus of claim 12, further comprising: a controller operable forcontrolling the first atmospheric water generator and the secondatmospheric water generator.
 16. The apparatus of claim 12, wherein: asubcooling system for cooling both the first atmospheric water generatorand the second atmospheric water generator.
 17. The apparatus of claim16, wherein the subcooling system comprises: a first expansion deviceassociated with cooling the first atmospheric water generator; and asecond expansion device associated with cooling the second atmosphericwater generator.
 18. The apparatus of claim 17, wherein the subcoolingsystem further comprises: a compact screw compressor; and a singlecondenser.
 19. The apparatus of claim 13, further comprising: a pump forpumping water through the water treatment system; and a controlleroperable for controlling the pump, the first atmospheric watergenerator, and the second atmospheric water generator.
 20. A methodcomprising: providing the apparatus of claim 1; and operating theapparatus to produce water from the air.
 21. A method comprising:providing the apparatus of claim 12; and operating the apparatus toproduce water from the air.
 22. A method comprising: providing anatmospheric water generator; providing a subcooling system; controllinga compressor and an expansion device of the atmospheric water generatorand the subcooling system.
 23. The method of claim 22, furthercomprising: collecting water condensed by the evaporator.
 24. The methodof claim 23, further comprising: sterilizing, filtering, andmineralizing the collected water.
 25. The method of claim 23, furthercomprising: pumping water the collected water through a water treatmentsystem; passing water from the water treatment system to an output ofthe atmospheric water generator; and the controlling further comprisescontrolling the pump.
 26. A method comprising: providing a firstatmospheric water generator; providing a second atmospheric watergenerator; and collecting water condensed from both the firstatmospheric water generator and the second atmospheric water generatorin a container.
 27. The method of claim 26, further comprising: treatingthe collected water.
 28. The method of claim 27, wherein: the treatingcomprises sterilizing, filtering, and mineralizing the collected water.29. The method of claim 26, further comprising: providing a subcoolingsystem; and cooling both the first atmospheric water generator and thesecond atmospheric water generator using the subcooling system.
 30. Themethod of claim 29, wherein the subcooling system comprises: a firstexpansion device associated with cooling the first atmospheric watergenerator; and a second expansion device associated with cooling thesecond atmospheric water generator.
 31. The method of claim 26, furthercomprising: pumping collected water through the water treatment system;and using a controller to control the pump, the first atmospheric watergenerator, and the second atmospheric water generator.